Thursday, February 23, 2012

Well, my weekdays haven’t been too interesting (more feeding larvae and collecting butterflies), but I had a really nice weekend (Feb 18-19). On Saturday I woke up early, clambered into a van with 11 other researchers, and went to a beach about two hours away. It was quite idyllic: black sand, thatched cabanas, waves perfectly-sized for body surfing, and not a shark, jellyfish, or sharp rock in sight. I spent most of the day shredding the gnar, but also did my fair share of lounging around, eating junk food. It was, in a word, fantastic.
As you probably know, I’m posting this right around the start of Lent, which means that the past week or so in Panama has been Carnival (perhaps most famously celebrated in Brazil). We here at STRI celebrated Carnival last Sunday. Gamboa is a rather small place, and our celebration was also rather small. We divided Gamboa in half, and each “neighborhood” made a parade float out of a truck and nominated a queen to dance on the float. We had a very short, very small “culeco” around Gamboa, which is a parade with music and water fighting. The parade quickly dissolved into just a water fight, which lasted for a few hours, Then we dried off, fired up some grills, and had a massive barbecue, which evolved into a party that went late into the night.
Unfortunately for my readers, I was too busy enjoying myself to catalog these experiences with photos, so I don’t have any to post. Instead, I have something just as enthralling as pictures: science!

Science Break 1- Species

The easy way to explain what I do here in Panama is to say “I use butterflies to study evolution.” I thought I might try to expand on that with some posts that actually explain the science I’m doing. My hope is that I’ll be able to explain everything in simple enough terms that my even my readers whose high school biology classes were decades ago will be able to understand. Feel free to post questions in the comments and I can try to clarify things.
I’ll start by looking at a word that we all know and use, but don’t often think deeply about: “species.” We all know that, say, tigers and mosquitoes are different species, but hardly ever think about why that is. In evolutionary biology, “species” can be defined in a number of ways, but perhaps the most common definition is the biological species concept, which says that species are defined by whether or not populations (groups of organisms) can mate with each other and produce viable offspring. Populations that can’t interbreed are separate species. Populations that can interbreed are the same species. When populations can’t mate with each other, we also say they are “reproductively isolated.” Reproductive isolation is simply a measure of populations’ inability to mate with each other. We can apply these definitions to a real world example. Tigers and mosquitoes can’t mate with each other and produce tigsquitoes, thus they are reproductively isolated and are separate species.
Unfortunately, it’s not always as simple as the tigsquito example. Take horses and donkeys, for instance. We consider them different species, yet they can mate and produce a hybrid, mules. Are donkeys and horses part of the same species? The answer, unsurprisingly, is no. Mules are sterile, which means they aren’t “viable offspring”, and thus horses and donkeys really are separate species.
Looking at these two examples, we see that there are different levels of reproductive isolation, even between things that are definitely species. Tigers and mosquitoes are (in comparison to each other) slightly more reproductively isolated than horses and donkeys: the former can’t mate at all, while the latter can, but produce sterile offspring. Reproductive isolation, then, exists along a continuum. One pole is zero reproductive isolation: the organisms within population(s) can mate with each other and produce offspring with no problem. At the other pole, we have total reproductive isolation: the populations can't mate with each other at all. In between, things can get pretty tricky, but I won’t discuss that until my next entry, which will be on speciation: they process of creating new species.

Monday, February 13, 2012

I’ve been mostly on my own for the last week, as my boss has been taking a course in a new molecular genetics technique at Naos, the STRI laboratory facilities. As such, my week hasn’t been too exciting, filled mostly with collecting butterflies and feeding caterpillars. Here are some highlights.

I had Feb. 4 off, so I slept in, made a nice breakfast, and then went into Panama City with another researcher for the afternoon. We got a ride to the main terminal, then took a taxi to casco viejo, the older and more touristically desirable part of the city. Taxi rides in Panama City can be interesting. Most taxis are meterless and privately operated: fares are determined by negotiation before the ride begins. My obvious gringo-ness and woeful Spanish skills make me an easy target, so I’ve been quickly learning what fair prices are for various trips around the city so that I don’t get ripped off. On this day we found an agreeable cab driver who immediately put in a “Musica en Ingles” CD (included "Total Eclipse of the Heart") once we got in the cab, told us about the differences between male and female cops, and spoke appreciatively of the muchachas in Panama.
After our arrival in casco we got some fancy gelato, then wandered around and took in the views. Casco viejo (and I suppose Panama City in general) is an interesting mix of the developed and undeveloped. One block might be developed, with nice restaurants and clubs, and the next street over will be full of semi-collapsed houses and trash.

On Thursday the 9th I went to Barro Colorado Island (BCI), an island in Lake Gatun/the Panama Canal. Once a hilltop in the forest, BCI became an island upon the flooding of the forest when the canal was constructed, and the Smithsonian has maintained a base there for almost 100 years. I went to see a talk there on Thursday night, and then stayed until Friday morning. It was a great place to visit: the forest is more pristine than the area around Gamboa, and the trails are far less invasive. I saw an anteater, howler monkeys, and capuchins. The ride to and from the island was also noteworthy. Our small boat shared the waterway with the massive Panamax cargo ships that are constantly traversing the canal. It was incredible to see them (fairly) up close.

Overall, the last few days have been going well: the weather has been extremely nice, I’ve become quite confident driving around Gamboa in a manual transmission truck, and I even saw two common basilisks (perhaps better known as the Jesus Christ lizard) run across water.

Hazy day, but a view of fishing boats, with Panama City in the background.

The Titan floating crane, one of the largest in the world. The only surviving model of three such cranes built by Nazi Germany, it was captured by the US and used in California before going to Panama in 1999.

When we catch butterflies, we store them in glassine envelopes until we get them back to the insectaries.

One of our study species: Heliconius melpomene rosina. Notice how the yellow band on the lower wing doesn’t extend all the way to the edge of the wing.

A Jesus Christ Lizard, not currently running miraculously.

Heliconius erato, a mimic of our study species. It has very few visible differences, the major one being that the yellow band on the lower wing extends all the way to the wing edge.

Thursday, February 2, 2012

The last few days have seen me settle into something of a routine: in the morning I go out (sometimes alone, sometimes with others) to collect butterflies, in the afternoons I do various work in the insectaries, mostly taking care of larvae. Some other happenings of note:
On the 29th I had a glorious day off, spent doing nothing more than reading in a hammock all day.
On the 31st we took a trip into Panama city to take care of some administrative stuff and get my STRI driver’s license at the main STRI campus. Afterwards, we went to a different, incredibly fancy mall (think Cartier, Tiffany’s, and Hermes) to buy a few supplies and go see a movie at the “VIP Theater,” which has leather recliners for seats, waiters who deliver food, and costs about what you’d pay for a normal movie in the US.
The 1st commenced with manual transmission driving lessons, as I’d managed to make it this far without ever learning to drive stick, and all the STRI trucks are manual. Fortunately, I knew how to drive stick in theory, and the trucks here, with clutches flogged by hundreds of first-timers like me, are very forgiving. However, we did get stranded outside of Gamboa for a few hours when a Canal Authority truck (carrying liquid dynamite for dredging) crashed on the one-lane bridge into Gamboa and had to be lifted off with a crane.

Up until this point, I didn’t have internet at my apartment, so uploading pictures and movies wasn’t easy. I now have internet, so I’ll be able to post those more often.